The U.S. obesity epidemic now affects 1 in 3 adults. As our population ages, obese persons are growing older and increasingly need long-term care services at a significantly younger age than their non-obese peers. Our analysis shows that over the last 10 years, there has been a significant increase in the proportion of nursing home (NH) residents who are obese, with 1 in 4 residents now severely obese (BMI ? 35). Ensuring high quality care for all NH residents is a national priority, and resident safety is a priority issue. Nevertheless, a specific focus on the safety of obese residents is lacking. Emerging, albeit sparse, research shows that obesity complicates NH care. Obese residents have significantly more functional limitations, require significantly more assistance from staff to perform basic ADLs, have higher rates of urinary catheterization, and have different nutritional needs than non-obese residents. Specific protocols are required for their care to prevent adverse events (e.g., skin breakdown and falls). Two- thirds of NH directors who responded to our survey on their experience with obese residents reported significant concerns about being prepared to care for them. In addition, research indicates that obese residents are concentrated in NHs with poor quality of care. These results indicate that obese persons needing long-term care likely reside in unsafe environments. Poor and unsafe NH care leads to adverse safety events. Differences in care needs, disparities in care received, and reports of negative outcomes provide ample evidence to justify further study of the safety of obese residents in U.S. NHs. The specific goals of our proposed mixed-methods study are to describe disparities in adverse safety events among obese NH residents, factors which lead to higher rates of adverse safety events among obese residents, and develop data collection tools to inform best practices that can be used to reduce adverse safety events among obese residents. We have assembled a team of experts in the study of obesity in NHs, NH clinical care, NH structures and performance, organizational theory, and, statistical methods to undertake this innovative study. We will use existing data to document and assess differences in outcomes by obesity status and to examine associations between key factors and NHs with high rates of adverse resident safety events among obese residents. Through key informant interviews, we will explore NH directors' experience in the care of obese NH residents and obtain input on how to improve NH environments and minimize the risk of adverse safety events among obese residents. Our proposed study is innovative, focusing on an understudied, but important and rapidly emerging, vulnerable NH resident group?the obese, and it will have significant impact, by enhancing knowledge, informing further research, and identifying actionable strategies to improve patient safety among AHRQ priority populations (elderly and people with disabilities).